1. Technical Field
The present disclosure relates to apparatus and methods in the onshore and marine (offshore) hydrocarbon exploration, production, drilling, well completion, well intervention, and leak containment fields. More particularly, the present disclosure relates to release tools for inside blowout preventers.
2. Background Art
A “blowout (or blow out) preventer”, commonly known as a “BOP”, is a valve that may be used to prevent a well, usually a hydrocarbon producing well, from flowing uncontrollably. An “inside BOP” (also sometimes referred to as an “internal BOP”, “IBOP”, “kelly valve”, or “kelly cock”) is a BOP inside a drillpipe or drillstring, usually used to prevent the well from flowing uncontrollably up the drillstring. Industry standards require having an IBOP for every string of pipe in the hole on every rig that is working.
Currently, IBOPs, which may weight 300 pounds or more, have no lifting eyes on their cap (also referred to as a “release tool”) or otherwise, although separate lifting devices that attach to the drillpipe and/or IBOP may have one or more lifting eyes, as taught in U.S. Pat. No. 4,291,762. They have been this way for many years. FIG. 1 is a side elevation view, partially in cross-section, of a non-limiting representative example of such an IBOP. There are many types of IBOP, and the present disclosure is relevant to all. U.S. Pat. Nos. 2,647,728; 4,403,628; 4694855; 4294314; 4478279; 5,507,467; 8,443,876; 8,443,877; 3,667,557; 3,835,925; 3,861,470; 4,291,762; 7,137,453; 7,950,668, and 7,108,081; and U.S. Published patent application no. 2013/0043044A1 all describe various types of IBOPs and/or accessories for same, such as actuators for IBOPs. Other examples of IBOPs may presently be found on the Internet websites of Global Manufacturing and M&M Industries. All of these patents and published patent applications are incorporated herein by reference.
In current practice in the field, the drilling rig workers tie a chain, cable, or strap around the IBOP valve cap to pick up the cap and the IBOP valve to which it is attached using a rig hoist and stab it into the drillpipe. The valve must be open (as shown in FIG. 1) in order to screw it into the drill pipe. If closed the pressure will blow it out before the threads can be started. The drilling rig workers turn the valve clockwise by hand to screw it into the drillpipe. In some instances, rig workers grab side handles (round rods welded to the release tool, as depicted in FIG. 1) and turn it with the round rods. Then they loosen the lock screw to release the rod holding the valve open. Then they tighten the threads with the rig tongs and the well is secure. Mud or other drilling fluid may then be pumped through the valve down hole but no pressurized fluids may come out of the drillpipe. One of the above patents, U.S. Pat. No. 4,403,628, implies in Col. 3 of the patent that assembling an IBOP into a drill stem and removing the IBOP therefrom as just described, including lifting and manipulating the IBOP, is conveniently performed, but this is contrary to experience, as accidents can and have occurred. Rig personnel safety is of utmost concern. The inventor herein personally knows of several accidents where the old style cap/release tool and IBOP valve slipped off the chain, cable, or strap, dropping the IBOP. While the “iron” (slang term for rig tools) is used to being dropped and banged around the rig, the rig workers have the difficult tasks of not only using the rig hoist to pick up the IBOP/release tool, using chains or otherwise, but picking it up straight (vertical or substantially vertical) to align with and screw onto the working drillpipe, which more often than not has fluids and possibly solids escaping out at a high rate. Experience shows that when rig workers are required to make a loop with a chain, cable, rope, or strap around the whole valve (for example around two handles 21) it rarely if ever picks up straight; it is then necessary to attempt to get it straight to get threads 20 on the lower end started in the drillpipe threads. In the meantime, the valve or other rig components may shift position and the valve slips off the chain, with potential to injure rig workers, and without stopping flow from the drillpipe. Complications only increase on offshore rigs, whether working subsea or “dry” at the surface on the rig.
As may be seen, current practice of installing and removing IBOPs may not be adequate for all circumstances. There remains a need for more robust IBOP release tool designs, particularly for apparatus and methods allowing safe and quick connection/disconnection and ease of alignment, without extra tools, lifting frames, or effort. The apparatus and methods of the present disclosure are directed to these needs.